Electrical connector



B. J. JOHANSON 3,212,052

ELECTRICAL CONNECTOR Filed Aug. 6, 1962 p v v 28a 52 26b 28b 28b 64 42 e4 44 "V 30 30 30 giving 56 3o if: 66 a; 6G

p a w 56 N 25 I] b 23 I l 60 6o l 16 lf le 12 H Fl6.5 FIG-6 Inventor 567756 J Janao/z United States Patent 3,212,052 ELECTRICAL CONNECTOR Bengt J. Johansou, Des Plaines, Ill., assignor to United- Carr Incorporated, a corporation of Delaware Filed Aug. 6, 1962, Ser. No. 215,078 1 Claim. (Cl. 339-217) The present invention relates to an improved electrical connector and more particularly it relates to a connector vwherein the contact element is easily insertable within become one of prime importance. It can readily be seen that the elements of the individually small assemblies become miniaturized to the point where previously normal manufacturing tolerances now become unacceptable and adherence to previously normal tolerance standards would result in completely unacceptable finished products.

The provision of small self locking electrical contact elements for electrical connectors present such a problem.

Normally such contact elements are manufactured of a suitable electrically conductive material, such as copper or brass or the like, while the insulating body within which the element is to be inserted is conventionally molded of bakelite, phenol or other suitable dielectric. Each of the materials employed in the manufacture of such components possesses inherent physical characteristics such as shrinkage, elasticity, and thermo-elastic properties wherein the materials will expand or contract under varying thermal conditions.

The present invention represents an improvement in the self locking and self positioning type of assembly. While prior art devices of the same type required extremely careful and precise machining and meticulous attention to detail and tolerances, the present element may be economically manufactured within reasonable tolerances. The precision required of prior art devices obviated the possibility of economical mass production of the electrical connectors and thus the cost of the items made them generally unattractive.

In accord with the present invention a contact element is provided having two pairs of resilient fingers, one pair being adapted to engage the insulating body to position and lock the contact element within the body and the other pair being adapted to receive and electrically engage the electrical probe or terminal to be inserted within the contact element to define an electrical interconnection therebetween.

It, therefore, is a general object of the present invention to provide an improved electrical connector.

A further object of the present invention resides in the provision of an improved electrical connector having an improvedself positioning and self locking electrical 1 contact element.

Another object of the present invention resides in the provision of an improved electrical connector having an improved electrical contact element that is easily insertable into the insulating body opening of the connector.

Still a further object of the present invention resides 3,212,652 Patented Oct. 12, 1965 in the provision of an improved electrical connector that is readily manufactured within reasonable tolerance limits.

A further object of the present invention resides in the provision of an improved electrical connector that is economical to manufacture and that is easy to assemble and use.

To achieve these objects, an electrical. connector is provided which includes an insulating housing having a plurality of spaced openings extending theret-hrough. Each of said openings defines two shoulder portions, one shoulder portion being positioned near each end of each of the openings. A generally tubular electrical contact or conductive member, composed of a suitable conductive metal such as brass, copper, or the like, is adapted to be received within each of the openings in the insulating body. The conductive member defines two pairs of flexible fingers at one of its ends, which fingers are in spaced relation to each other. One pair of fingers is positioned slightly inwardly of the other pair of fingers so that the two inward fingers may achieve a more intimate contact with a metal prong or terminal adapted to be inserted therein. Each conductive member further defines a pair of flanges along its length. One flange is disposed adjacent the deformable fingers, and the other flange at the opposite end of the conductive member. The flanges are spaced in relation to the shoulder portion of the insulating housing so that upon insertion of the conductive member into the insulating housing each of the flanges of the conductive member comes into interfacial contact with each of the corresponding shoulder portions of the housing to provide an immovable emplacement of the conductive member within the insulating housing.

The disposition of the flexible fingers of the conductive member serves to insure a close electrical. contact with the metal probe and also to further fix the conductive member Within the insulating housing. This is achieved by the configuration of the flexible fingers. The pair of spatially opposed fingers which are slightly biased inwardly of the other pair of fingers serves to assure a better electrical contact with an inserted probe than would be the case if all four fingers lay on the periphery of a common circle. The other two resilient and deformable fingers make locking contact with the shoulders of the insulating housing to further anchor the conductive member in the insulating housing.

The novel features which are believed to be characteristic of the present invention are set forth with particularity in the appended claims. The invention itself, how ever, together with further objects and advantages thereof, will best be understood by reference to the following description taken in connection with the accompanying drawings, in which:

FIGURE 1 is a plan view of the contact element employed in the electrical connector of the present invention;

FIGURE 2 is an end view of the contact element of FIGURE 1 taken from the flexible finger end of the element;

FIGURE 3 is a top view of the electrical connector of the present invention illustrating the contact element in assem'bled relation with the insulating body;

FIGURE 4 is a view similar to that of FIGURE 3 but with the mating prong or terminal inserted into the terminal receiving opening defined by the fingers of the contact element of the connector;

FIGURE 5 is a side elevational view in cross-section taken along line 5-5 of FIGURE 3;

FIGURE 6 is a side elevation in cross-section taken along lines 6-6 of FIGURE 3; and

FIGURE 7 is a side elevation in cross-section taken along lines 7-7 of FIGURE 4 illustrating the terminal inserted into the terminal receiving opening of the electrical connector.

Referring more particularly now to FIGURE 1, the electrical contact element is illustrated generally at 10. The element 10 includes a main body portion 12 and finger portions, indicated at 14.

The main body portion 12 of the contact element 10 includes a projection 16 having an opening 18 extending internally thereof for substantially the full length of the main body portion. A second opening 20 may extend through the wall of the main body portion 12 to intersect the internal opening 18 therein adjacent the inner terminal of said opening 18 to provide access to the base of said opening 18. A collar 23 is provided about the outer periphery of the main body portion 12 in spaced relation to the free end of the projection 16 to define a shoulder 24 thereon.

The finger portion 14 of the contact element 10 extends away from the projection 16 of the main body portion. The finger portion 14 includes two pairs of fingers 26a 26b and 28a-28b, respectively. Each of the fingers of the finger portion of the contact element are separated by a groove 30 extending longitudinally of the finger portion for a substantial portion of its total length. The grooves 30 are provided to permit inward fiexure of the individual fingers of the finger portion to facilitate insertion of the contact element 10 into the opening in the insulation body, to be described in detail below.

As indicated in FIGURE 2, the fingers 28a and 28b are disposed slightly inwardly of the fingers 26a and 26b. The inner portions 32 and 34, respectively, of the fingers 28a and 28b extend within the base circle 36 defined by the inner portions 38 and 40, respectively, of the fingers 26a and 261).

Each of the fingers 26a and 26b defines a shoulder portion 42 at the base thereof. Each of the fingers 28a and 28b defines a similar shoulder portion 44 at the base thereof. The shoulder portions 44 of the inwardly disposed fingers 28a and 28b preferably are provided in coplanar relation with the shoulder portions 42 of the fingers 26a and 26b or are disposed more toward the terminals of the finger portions than the shoulder portions 42 of the opposed pair of fingers. The provision of the shoulder portions in this manner permits economical manufacture of the contact element and insulating housing within which it is to be received and further assures positive placement and locking of the contact element within the insulating housing opening.

As indicated in FIGURES to 7, the terminal portions of each of the finger portions 26a, 26b, 28a and 28b define an enlarged head portion having flaring portions at the outer terminals thereof. The flaring portions 50 on the inner terminal portion of each of the fingers is provided to facilitate insertion of the terminal or electrical contact prong into the central terminal receiving opening defined between the fingers. The flaring portions 52 on the outer periphery of the terminal portion of each of the fingers are provided to facilitate insertion of the contact element into contact element receiving opening defined within the insulating body, as described hereinbelow.

The insulating body, indicated generally at 56 in FIG- URES 5 to 7, may be of phenol resin, Bakelite or any other suitable dielectric material. The insulating body illustrated here for purposes of describing the invention is adapted to receive only one contact element 10. It should be observed, however, that the insulating body may be provided of any desired size and configuration to receive any number of contact elements in accord with the teachings herein without departing from the spirit and scope of the invention disclosed.

The insulating body 56 is provided with an opening extending therethrough, said opening being defined by relatively large diameter end openings 58 and 60, respectively being interconnected by the restricted opening portion 62. Shoulder portions 64 and 66 are defined at the intersection of the restricted opening 62 with the end openings 58 and 60, respectively. As indicated above, the dimensional tolerances of the opening within the insulating body need not be severe with the connector of the present invention. It should be observed that with connectors of the prior art it was essential to give detailed attention to tolerances of both the opening in the insulating body and the electrical contact element. The length of the restricted portion of the opening should be maintained within reasonable tolerance limits in order to assure proper positioning and locking of the contact element within the opening of the insulating body.

The contact element 10 is inserted into the opening in the insulating body 56 by, for example, urging the terminal portions of the fingers into the large diameter opening 60 at one end of the insulating body. The finger portions may be freely inserted into this opening in view of the fact that the largest diameter of the finger portions is smaller than the diameter of the opening 60 and there is nothing, therefore, to restrict insertion of the fingers therein. The restricted portion 62 of the insulated body opening, however, is smaller in diameter than the smallest diameter of the outwardly disposed fingers 26a and 26b of the finger portion 14. It can readily be seen, then, that in order for the contact element to be inserted into and through the restricted opening, the fingers of the finger portion must be adapted to flex inwardly to define a diameter sufiiciently small to pass through the restricted opening 62.

The flared portions 52 on the outer periphery of the terminals of each of the fingers will serve to earn the fingers inwardly to define a smaller total diameter thereacross. The portions 52 will ride upon the shoulders 66 between the restricted portion 62 and the opening 60 to force the fingers inwardly of the electrical contact member. The slots 30 defined between each of the finger portions must be of suflicient width and depth to assure that enough flexure of the fingers may occur to permit passage thereof through the restricted opening 62. The inwardly disposed fingers 28a and 28b, normally will not be deflected to a great extent in that the base circle defined about the outer periphery of these fingers will be only slightly larger than the diameter of the restricted opening. With such a construction, therefore, it is seen that the fingers of the contact element need not be flexed as much as if all of the fingers of the element lie within a common base circle. The largest measure of flexure with the present construction occurs within the outward ly disposed fingers 26a and 26b. Insertion of a contact element with this construction is easier than insertion of an element wherein all fingers are disposed in a common circle. There is also less tendency for either the fingers to be bent upon insertion or the inner portion of the insulation body opening to be damaged upon insertion of the contact element within the insulation body opening.

After the entire head portion of each of the fingers has traversed the length of the restricted portion of the opening, the fingers will flex outwardly to assume their static position in mutually spaced relation, the space therebetween being defined by the slots 30. In view of the fact that the diameter of the opening 58 in the insulating body 56 is larger than the largest diameter defined across the head portion of the fingers, there is nothing to restrict the fingers or to prohibit them from resuming their static positions. It should be observed that in the resumption of static positions by each of the fingers of the electrical contact element 10, the opposite pairs of fingers will be disposed in different common base circles with the pair 28a-28b being disposed slightly inwardly of the remaining pair.

Upon full entry of the head portion of the fingers 26a and 26b into the opening 58 in the insulating body, the shoulder portions 42 of each of said fingers will be urged outwardly into static positions and will define a base circle larger in diameter than the diameter of the restricted opening 62. It, thus, is readily seen that the shoulder portions 42 of the fingers 26a and 26b will be urged into interfacial abutting engagement with the shoulder 64 in the opening in the insulating body to prevent withdrawal of the electrical contact element in the direction in which it was inserted.

The main body portion 12 of the contact element 10 is provided with a collar 23 thereon in spaced relation to the shoulder portions of the fingers 26a and 26b. The collar 23 defines a shoulder 24 in conjunction with the main body portion, said shoulder 24 being positioned to face the shoulders 42 of the fingers. The distance between the shoulder 42 of the fingers 26a and 26b and the shoulder 24 of the main body portion is substantially equal to the lineal distance defined by the restricted opening 62 in the insulating body 56. It is readily seen that the positioning of the contact element 10 within the insulating body 10 is automatically realized upon insertion of the contact element within the opening in the insulating body. The shoulder 24 will come into abutting relation with the shoulder 66 at substantially the same time that the head portions of fingers 26a and 26b fully enter the larger diameter opening 58 of the insulating body. The abutment of shoulder 24 and 66 will prevent continued insertion of the contact element within the insulating body and the abutment of shoulder portions 42 and 64 will prevent withdrawal of the contact element from the opening in the insulating body.

The shoulder portions 44 of the fingers 28a and 28b may or may not be in abutting engagement with the shoulder 64 of the insulating body opening. It is not material whether these shoulder are in abutting relation or not, since they do not serve to define locking means for retaining the contact element 10 within the opening within the insulating body. As indicated hereinabove, the fingers 28a and 28b are disposed slightly inwardly of the fingers 26a and 2611. With the fingers 28a and 28b disposed slightly inwardly in their static positions there may be a small overlap of the shoulder portions 44 of the fingers and the shoulder portion 64 of the insulating body. However, the degree of overlap may not be suflicient, of itself, to assure retention of the contact element 10 within the opening in the insulating body. No such function is intended for the shoulder portions of the inwardly disposed fingers. It can be seen from FIGURE 5 that with such engagement only a very slight pressure would be required to dislodge the shoulders 44 from engagement with the shoulder 64 of the insulating body, and if this were the only means of locking the element 10 within the opening in the insulating body, the element 10 would be easily dislodged. Thus, it is essential that the two outwardly disposed fingers 26a and 26b serve to lockingly engage the element 10 within the insulating body opening, in conjunction with the shoulder 24 defined by the collar 23 on the main body portion 12.

As indicated in FIGURE 7, a terminal or contact prong 70 is adapted to be inserted into the central opening defined between the fingers of the contact element 10. The prong 70 first engages the outwardly flaring portions 50 of the fingers upon insertion thereof into the central opening and is guidingly directed into the central opening by said flaring portions. The prime engagement of the prong 70 is realized by the inwardly disposed fingers 28a and 28b. The diameter of the common base circle defined by the inner arcs 32 and 34 of the fingers 28a and 28b, respectively, is smaller than the diameter of the prong 70 to be inserted therebetween. As such, the prong 70 will flex the fingers 28a and 28b outwardly upon entry into the central opening defined between the fingers to assure positive electrical contact between the prong and the fingers and to assure a good electrical interconnection between the auxiliary equipment with which the prong 70 6 is associated and the electrical connector of the present invention.

Upon outward flexure of the fingers 28a and 28b the diameter defined between the outer extremities of the fingers will be larger than the diameter of the restricted opening 62 in the insulating body so that the shoulders 44 of the finger portions 28a and 28b will be adapted to abuttingly engage the shoulder 64 of the insulating body. This further enhances the locking characteristic of the electrical contact element 10 within the insulating body.

The outwardly disposed fingers 26a and. 26b will not be flexed outwardly any further by insertion of the prong into the central opening of the contact element 10 so that the outer dimension of the fingers 26a and 26b may be provided to be substantially the same as the diameter of the opening 58 in the insulating body. The above noted pair of fingers 26a and 26b, thus, provide the locking feature of the contact element disclosed herein.

The fingers 28a and 28b are inwardly disposed so as to assure good electrical contact between the fingers, and thus the contact element 10, and the prong 70 to be inserted therein.

If the fingers 26a-26b and 28a-28b were provided such that they all were in a common base circle, it can readily be seen that many difliculties would be presented. Such a construction would not permit either good locking characteristics or good electrical contact characteristics. It is not likely that both characteristics would be present with such a construction. In miniature components it would be observed that the shoulder portions 64 and 66 of the insulating body will be relatively small and as such there is very little surface area to grasp. In such small components, the tendency would be to provide a construction that that would result in the maximum grasping surface in order to assure an interlocking engagement between the electrical contact element and the insulating body. With such constructions all of the fingers would be formed on a maximum diameter substantially equal to the diameter of the larger openings of the insulating body in order to provide maximum engagement between the small surface area of the shoulders within the body and the shoulders on the fingers. If the fingers are provided such that they all are on such a maximum diameter, there is little or no room for fiexure of the fingers to permit easy entry of the prong 70 into the central opening in the contact element.

Conversely, if the fingers are all disposed inwardly to allow for flexure of the fingers and thus provide for easy insertion of the prong 70 into the central opening, the shoulders of the fingers may not adequately engage the shoulder of the insulating body and the electrical contact element would be too easily dislodged from the opening.

While I have shown and described a specific embodiment of the present invention it will, of course, be understood that other modifications and alternative constructions may be used without departing from the true spirit and scope of this invention. I therefore intend by the appended claim to cover all such modifications, and alternative constructions as fall within their true spirit and scope.

What I claim as new and desire to secure by Letters Patent of the United States, is:

A miniaturized electrical connector for receiving an electrical contact prong in a miniaturized assembly comprising in combination an insulating body having an opening extending therethrough, said opening having a restricted portion intermediate the end portions thereof, the junction of said restricted portion and the end portions of the opening forming first and second inwardly extending, axially spaced shoulder portions, a miniatur-ized electrically conductive contact element positioned Within the opening of the insulating body, said contact element having a main body portion and two pairs of opposed finger portions integral with and extending axial- 1y outwardly from one end of the main body portion forming an axially extending opening therebetween, the first pair of opposed finger portions being positioned radially inwardly of the second pair of opposed finger portions, said first pair of opposed finger portions, in use, adapted to receive and engage therebetween in located relation an electrical contact prong to be inserted therein, the second pair of opposed finger portions defining a projection adjacent its free ends and extending radially outwardly and engaging the first shoulder portion within the opening of said insulating body to prevent axial movement of the contact element within the opening in one direction, both pairs of finger portions adapted to be flexed inwardly of the main body portion for insertion into the opening of the insulating body 15 through the restricted portion thereof, said finger portions further being returnable to their static position upon entry of the contact element into the opening of the insulating body, said main body portion of the contact element having an outwardly extending shoulder member engaging in abutting relationship a second shoulder of the insulating body opening, said shoulder member being in axial spaced relation to the outwardly extending projection on the second pair of finger portions, the axial distance therebetween being substantially equal to the length of the restricted portion of the opening in the insulating body thereby defining means for positioning the contact element within the insulating body opening to prevent movement thereof in either direction.

References Cited by the Examiner UNITED STATES PATENTS 1,344,596 6/20 Schaefer 855 2,685,073 7/54 Damon 339217 FOREIGN PATENTS 1,224,474 2/60 France.

657,838 9/51 Great Britain.

JOSEPH D. SEERS, Primary Examiner. 

